• Title/Summary/Keyword: 탈탄산 반응

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Determination of Reactivity by MO Theory (Part 32). MO Studies of Substituent Effects on the Gas-Phase Decarboxylation of But-3-enoic Acid (분자궤도론에 의한 반응성 결정 (제32보). 3-부테노산의 기체상 탈탄산반응에 미치는 치환기 효과의 분자궤도론적 연구)

  • Jeoung Ki Cho;Ikchoon Lee;Hyuck Keun Oh;In Ho Cho
    • Journal of the Korean Chemical Society
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    • v.28 no.5
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    • pp.279-283
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    • 1984
  • ${\beta}$-Substituent effect on the reactivity of retro-ene decarboxylation of but-3-enoic acid was investigated theoretically. It was found that charge effect is important not only through ${\pi}$-electron transfer as has been claimed to rationalize experimental results but also through polarization as found for the $CH_3$ substituent. The reactivity was not determined by the charge effect alone but the HOMO-LUMO energy gap was also found to affect the reactivity. In general it was confirmed that the greater the ${\pi}$-electron donating power of the substituent, the greater is the reactivity.

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젓갈 중의 Histamine 함량

  • 허지연;황미경;양지영;장동석
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2000.10a
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    • pp.119-120
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    • 2000
  • 젓갈은 어패류의 육, 내장, 생식소 등에 식염을 가하여 부패를 억제하면서 자가 소화 및 미생물의 작용에 의하여 원료를 적당히 분해시켜 숙성시킨 제품으로 발효과정 중에서 생성된 유리 아미노산이나 저분자 펩타이드와 각종 방향성 성분에 의해 특유의 감칠맛과 풍미를 지니고 있다. 그러나 젓갈로 사용되고 있는 어류 중에서 특히 적색육 어류는 선도 저하와 더불어 증가된 Proteus morganii와 같은 세균에 의해서 생성된 decarboxylase의 탈탄산 반응에 의해 아미노산이 분해되어 유독 amine물질을 생성한다. (중략)

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Simulation on the Alternation of Limestone for Portland Cement Raw Material by Steel By-products Containing CaO (CaO 함유 철강 부산물을 활용한 시멘트 원료 석회석 대체 시뮬레이션)

  • Jae-Won Choi;Byoung-Know You;Min-Cheol Han
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.1
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    • pp.1-8
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    • 2023
  • In this study, to reduce CO2 emission in the cement manufacturing process, we evaluated the limestone that is used as a raw material for cement, substituted with steel slag by the various substituted levels. Based on the chemical composition of each raw materials including limestone, and blast furnace slow cooling slag, converter slag, and KR slag as an alternative raw material, we simulated the optimal cement raw mixture by the substitution levels of limestone. Test results indicated that the steel slags contain a certain level of CaO that can be used as alternative decarbonated raw materials, and it has enough to partially reduce the amount of limestonem. And we estimated the maximum usable levels of each raw material. In particular, it was confirmed that by using a mixture of these raw materials rather than using them one by one, the effect of reducing limestone was increased and CO2 emission from the cement manufacturing process could be reduced.

Maillard Reaction Products Formed from D-Glucose-Glycine, System and Their Formation Mechanism (D-Glucose-Glycine 계의 Maillard 반응생성물 및 그 생성기구)

  • KIM Seon-Bong;PARK Yeung-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.19 no.1
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    • pp.45-51
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    • 1986
  • Equimolar aqueous solutions of D-glucose and glycine were heated at $50^{\circ}C\;and\;95^{\circ}C$ at pH 6.7. The headspace volatiles and the ether extracts from the reaction mixture were analyzed by gas chromatography and gas chromatography-mass spectrometry using a fused silica capillary column. The major components formed were identified as diacetyl, three furfurals, two pyrroles, one furanone, two pyranones and two amides. In order to elucidate the formation mechanisms of the amides formed front amino-carbonyl reaction, two model systems were adopted. N-butylacetamide were formed as major components from diacetyl-butylamine ana glyoxal-butylamine systems, respectively. The results obtained suggest that such ${\alpha}-dicarbonyls$ as 3-deoxy-D-erythro-2,3-hexodiulose and diacetyl generated in the amino-carbonyl reaction react with amino compounds, amides then being formed by cleavage of the C-C bond in the ${\alpha}-dicarbonyls$.

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Biogenic Amines Formation and Content in Fermented Soybean Paste (Cheonggukjang) (청국장 중 biogenic amine의 함량 및 생성원인)

  • Han, Gyu-Hong;Cho, Tae-Yong;Yoo, Myung-Sang;Kim, Chun-Soo;Kim, Jung-Min;Kim, Hyun-Ah;Kim, Mi-Ok;Kim, Seong-Cheol;Lee, Sun-Ae;Ko, Yong-Suk;Kim, So-Hee;Kim, Dae-Byoung
    • Korean Journal of Food Science and Technology
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    • v.39 no.5
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    • pp.541-545
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    • 2007
  • The potential to produce biogenic amines was investigated in microbial strains isolated from fermented soybean paste, cheonggukjang. The typical levels of 11 biogenic amines, including putrescine, histamine, and tryptamine, were analyzed in commercial cheonggukjang. The tyramine and histamine levels in the samples ranged from 4.2 to 483.1 mg $kg^{-1}$ and 0.2 to $70.3mg\;kg^{-l}$, respectively. A total of 4 microbial strains of Bacillus sp. were isolated from cheonggukjang. The Bacillus sp. were identified as B. amyloliquefaciens, B. subtilis, and B. licheniformis based on phenotypic characteristics, which included using the VITEK system. The screening plate method for detecting amino acid decarboxylase positive microorganisms was performed. The results fer amino decarboxylation were positive, and biogenic amine formation was evaluated by the confirmation of amine-forming capacity.

A Study on the Characteristics of Manufactured Mg Crown on the Calcining Conditions of Dolomite (백운석의 소성 조건에 따른 제조 Mg crown의 특성에 관한 연구)

  • Hwang, Dae Ju;Yu, Young Hwan;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.59 no.4
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    • pp.611-625
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    • 2021
  • Mg crowns were manufactured using domestic dolomite (Ca·Mg(CO3)2) (20~30 mm). In order to manufacture the calcined dolomite (CaO·MgO), (a) electric furnace (950 ℃, 480 min) and (b) microwave furnace (950 ℃, 60 min) processes were used. As a result of XRD analysis, it was analyzed as (a) CaO 56.9 wt%, MgO 43.1 wt% by electric furnace process and (b) CaO 55 wt%, MgO 45 wt% by microwave furnace process. Even when the decarbonation reaction time of dolomite was shortened by 1/8 in microwave furnace process compare with electric furnace process, the calcined dolomite could be produced. The hydration reaction (ASTM C 110) is a standard for the hydration reactivity of calcined dolomite, and the calcined dolomite produced by electric furnace process showed a high hydration reactivity (max temp 79.8 ℃/1.5 minutes). Such hydration reactivity was occurred by only CaO hydration reaction and that was confirmed by XRD analysis. The calcined dolomite produced by microwave furnace process showed low hydration reactivity (max temp 81.7 ℃/19.5 minutes). Such low hydration reactivity was occurred by CaO and MgO hydration reaction due to the hydration reaction of CaO thereafter occurring of the hydration reaction of MgO, and that was confirmed by XRD analysis. The prepared Mg crown were 58.8 g and 74.6 g by electric furnace and microwave furnace processes, respectively, under the reaction conditions of 1,230 ℃, 60 min, 5 × 10-2 torr by silicothermic reduction.

The CO2 Emission in the Process of Cement Manufacture Depending on CaO Content (시멘트 생산과정에 따른 CaO 함량과 CO2의 발생량)

  • Kim, Sang-Hyo;Hwang, Jun-Pil
    • Journal of the Korea Concrete Institute
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    • v.25 no.4
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    • pp.365-370
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    • 2013
  • In this study, contents of limestone in cement manufactured by six domestic plants for Portland cement were investigated in terms of the strength and its relation to the $CO_2$ emission due to limestone material and its physical properties in cement manufacturing process. the relationship among CaO content, compressive strength, and $CO_2$ emission was surveyed for the limestone quantity in decomposition reaction and the loss of limestone quantity contained in each cement. As a result of $CO_2$ emission calculation for unit cement, it was found that the $CO_2$ emission due to decomposition of limestone was occupied 67% of total emission quantity. Furthermore, there was a difference in $CO_2$ emission quantity depending on the cement manufacturing process management. Also, it was shown that fossil fuel usage and material loss had a major influence as main factors of $CO_2$ emission. An increase in the CaO content in cement resulted in an increase in the compressive strength. On the contrary, CaO content and compressive strength were reduced with the growth of loss quantity of limestone. It was verified that the material and process management were more effective than CaO yield in cement manufacturing for $CO_2$ emission with the growth of $CO_2$ emission quantity. Pozzolanic materials such as PFA and GGBS in concrete mix affected the price, $CO_2$ emission and development of strength of concrete.

Structural determination of triterpenic acids in Prunellae Spica by fast atom bombardment tandem mass spectrometry (하고초의 생리활성 성분 Triterpenic Acids의 FAB-MS를 이용한 구조 규명)

  • Ahn, Young Min;Lee, Kang Ro;Hong, Jongki
    • Analytical Science and Technology
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    • v.21 no.4
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    • pp.245-258
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    • 2008
  • Five triterpenic acids as marker compounds were extracted and isolated from Prunellae Spica by column chromatography and reversed-phase high-performance liquid chromatography (HPLC), and their purity was determinated by HPLC (purity ${\geq}90%$). Molecular weight and elemental compositions of the five marker compounds were determined by fast atom bombardment high-resolution mass spectrometry (FAB-HRMS). The structural determination of the five marker compounds was carried out fast atom bombardment collision-induced dissociation tandem mass spectrometry (FAB-CID-MS/MS). The collision-induced dissociation (CID) of protonated molecules $[M+H]^+$ and deprotonated molecules $[M-H]^-$ produced diverse product ions due mainly to retro Diels-Alder reaction (RDA), dehydration and decarboxylation. Moreover, the CID-MS/MS spectra of the $[M-H]^-$ ions were observed charge-remote fragmentation (CRF) patterns. On the basis of interpretation of CID-MS/MS spectra, structural elucidation of triterpenic acids isolated from Prunellae Spica was clearly performed.

An Experimental Study on the Carbonation Depth of Cement Paste Using Carbonation Reaction Accelerator (탄산화 반응 촉진제를 이용한 시멘트 페이스트의 탄산화 깊이에 관한 실험적 연구)

  • Seok-Man Jeong;Wan-Hee Yang;Dong-Cheol Park
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.349-354
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    • 2023
  • This study wa s conducted a s pa rt of ma ximizing the use of ca rbon dioxide by a pplying CCU(Ca rbon Ca pture, Utiliza tion) a mong technologies for reducing CO2 in the cement industry. In a carbon dioxide curing environment, changes in carbonation depth and changes in basic physical properties by age due to the mixing of carbonation reaction accelerators were usually targeted at Portland cement paste. In addition, in order to check the fixed amount of CO2 in the concrete field, a thermal analysis method was applied to evaluate CaCO3 decarbonization at high temperatures. As a result of the evaluation, it was confirmed that the carbonation depth in the cured body significantly increased due to the incorporation of CRA in the carbonation depth diffusion performance. In addition, it was confirmed that the weight reduction rate increased by 23.8 % and 40.77 %, respectively, compared to Plain, in the order of curing conditions for constant temperature and humidity and curing conditions for carbonation chambers, so it was confirmed that the amount of excellent CaCO3 produced by the addition of CRA increased as the concentration of CO2 increased.

Mineralogical Analysis of Calcium Silicate Cement according to the Mixing Rate of Waste Concrete Powder (폐콘크리트 미분말 치환율에 따른 이산화탄소 반응경화 시멘트의 광물상 분석)

  • Lee, Hyang-Sun;Song, Hun
    • Journal of the Korea Institute of Building Construction
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    • v.24 no.2
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    • pp.181-191
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    • 2024
  • In the realm of cement manufacturing, concerted efforts are underway to mitigate the emission of greenhouse gases. A significant portion, approximately 60%, of these emissions during the cement clinker sintering process is attributed to the decarbonation of limestone, which serves as a fundamental ingredient in cement production. Prompted by these environmental concerns, there is an active pursuit of alternative technologies and admixtures for cement that can substitute for limestone. Concurrently, initiatives are being explored to harness technology within the cement industry for the capture of carbon dioxide from industrial emissions, facilitating its conversion into carbonate minerals via chemical processes. Parallel to these technological advances, economic growth has precipitated a surge in construction activities, culminating in a steady escalation of construction waste, notably waste concrete. This study is anchored in the innovative production of calcium silicate cement clinkers, utilizing finely powdered waste concrete, followed by a thorough analysis of their mineral phases. Through X-ray diffraction(XRD) analysis, it was observed that increasing the substitution level of waste concrete powder and the molar ratio of SiO2 to (CaO+SiO2) leads to a decrease in Belite and γ-Belite, whereas minerals associated with carbonation, such as wollastonite and rankinite, exhibited an upsurge. Furthermore, the formation of gehlenite in cement clinkers, especially at higher substitution levels of waste concrete powder and the aforementioned molar ratio, is attributed to a synthetic reaction with Al2O3 present in the waste concrete powder. Analysis of free-CaO content revealed a decrement with increasing substitution rate of waste concrete powder and the molar ratio of SiO2/(CaO+SiO2). The outcomes of this study substantiate the viability of fabricating calcium silicate cement clinkers employing waste concrete powder.